On the map Episode 6: The Experiment: At the start of the level when you meet up with Boldur. He takes you to an area to defend the Amenine Observatory cores and when the wave starts and enemies spawn in to attack, if you yourself go in and destroy all the teleporters before the wave is finished the game bugs out and now no enemies spawn in and the wave does not continue. It does not show as finished nor does the bar go down. Which means there is nothing you can do from that point on in the mission. The only thing you can do to potentially fix this problem is to quit and reload the mission and this time try not destroying the teleporters. This may not be a common or serious problem but I feel it is a bug that should be fixed regardless.